Patent DE-102012005090-B3 (DE)
Title: Filling hollow profile with metal foam, comprises inserting precursor material into hollow profile, inserting into induction device having induction coil and -tool coupling induction field generated by induction coil, and foaming precursor
Inventor: HANNEMANN CHRISTIAN
IPC: B22F3/00
Filed: 2012-03-12
Granted: 2013-06-27
Abstract: Filling a hollow profile (2) with metal foam, comprises e.g.: inserting a foamable precursor material (5) into a hollow profile; inserting the hollow profile into an induction device; and foaming the precursor material. The induction device comprises an induction coil and an induction tool (6) coupling an induction field generated by the induction coil. The hollow profile is inserted into the induction device such that the hollow profile is at least partially externally surrounded by the induction coil and the induction tool is at least partially externally surrounded by the hollow profile. Filling a hollow profile (2) with metal foam, comprises: inserting a foamable precursor material (5) into a hollow profile; inserting the hollow profile into an induction tool, or pushing the induction apparatus into the hollow profile; and continuously and inductively foaming the precursor material within the hollow profile. The induction device comprises an induction coil and an induction tool (6) coupling an induction field generated by the induction coil. The hollow profile is inserted into the induction device, or the induction device is pushed into the hollow profile such that the hollow profile is at least partially externally surrounded by the induction coil and the induction tool is at least partially externally surrounded by the hollow profile. The precursor material is foamed by heating the induction tool using the induction field generated by the induction coil, and discharging the obtained thermal heat to the precursor material by induction tool. Independent claims are also included for: (1) an apparatus for the above method, comprising an induction coil, into which a hollow profile with a foamable precursor material is inserted, and an induction tool that couples an induction field generated by the induction coil, is arranged in the induction coil; (2) a continuous production of hollow profiles with metal foam interior structure, comprising (a) providing a profile blank with a sheath material and a foamable core material, (b) passing the profile blank through a matrix to form a strand-shaped profile with an external hollow profile made of the sheath material and an inner layer made of the foamable core material, and (c) passing the strand-shaped profile through the induction device, in which the inner layer is foamed by inductive heating, and a matrix core tool is arranged within the matrix such that, during passing the profile blank through the matrix, a strand-shaped-, double-layer hollow profile with the outer sheath material and the inner foamable core material is formed, and the induction device comprises a ferromagnetic mandrel, preferably a steel mandrel arranged in the induction coil, where the strand-shaped hollow section is passed through the induction device such that that the hollow profile is at least partially externally surrounded by the induction coil and the mandrel is at least partially externally surrounded by the hollow profile, and the mandrel is heated through the induction field generated by the induction coil and the heat is discharged to the inner layer from the mandrel, for foaming the inner layer, and the mandrel and the matrix core tool are mounted on the opposite ends of a lance; and (3) a plant for carrying out the above method, comprising (i) an extrusion molding apparatus with a matrix for passing a profile blank to form a strand-shaped main profile with the outer hollow profile and the inner core layer, (ii) an induction device subsequent to the extrusion molding apparatus in direction of the passage, to foam the inner layer of the strand-shaped profile through induction heating, immediately after discharging from the extrusion molding machine, (iii) a matrix core tool arranged within the matrix of the extrusion molding apparatus, to form a strand-shaped-, double-layer hollow profile with an outer layer made of a sheath material and an inner layer made of foamable core material, during drawing and/or passing the profile blank through the matrix, and (iv) induction device, which comprises the steel mandrel arranged in the induction coil.